南非草药蝴蝶亚仙人掌对db/db小鼠肝脏糖脂代谢和PI3K/Akt/FoxO1信号通路的影响

Effect of South African Herb Hoodia gordonii on Liver Glucolipid Metabolism and PI3K/Akt/FoxO1 Signalling Pathway in db/db Mice

目的:观察南非草药蝴蝶亚仙人掌(HG)对糖尿病db/db小鼠糖脂代谢的影响,基于磷脂酰肌醇3激酶(PI3K)/蛋白激酶B(Akt)/叉头转录因子O亚族1(FoxO1)信号通路探索HG对db/db小鼠肝脏可能的机制。方法:30只db/db小鼠根据空腹血糖随机分为5组:模型组、二甲双胍组(0.195 g·kg^(-1))、HG低剂量组(0.39 g·kg^(-1))、HG中剂量组(0.78 g·kg^(-1))、HG高剂量组(1.56 g·kg^(-1)),每组6只,并设6只m/m小鼠为正常组。正常组和模型组小鼠给予9 mL·kg^(-1)等体积生理盐水灌胃。每周检测各组小鼠体质量、饮食水量及空腹血糖。连续给药6周后取材,测空腹血清胰岛素(FINS)、低密度脂蛋白(LDL)、总胆固醇(TC)、甘油三酯(TG)、丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)、尿素(UREA)、肌酐(CREA),取肝脏包埋切片行苏木素-伊红(HE)、过碘酸雪夫(PAS)及油红O染色。免疫组化检测肝脏中PI3K p85、磷酸化(p)-Akt和p-FoxO1的磷酸化蛋白表达。实时荧光定量聚合酶链式反应(Real-time PCR)检测肝组织中PI3K、Akt、FoxO1 mRNA的表达变化。结果:给药干预6周后发现,与模型组比较,HG低、中、高剂量组小鼠的空腹血糖均明显下调(P<0.05);HG低、中剂量组胰岛抵抗指数水平均有明显降低(P<0.05);HG低、中、高剂量组均可明显降低TC、TG与LDL表达水平(P<0.05,P<0.01);病理方面,与模型组比较,蝴蝶亚仙人掌可缓解小鼠肝细胞脂肪样变性,减轻肝脏内脂滴体积和含量,并一定程度增加肝脏内糖原颗粒的分布。免疫组化检测发现,与模型组比较,HG低、中、高剂量组PI3K p85蛋白表达均显著增加(P<0.01);HG中、高剂量组p-Akt蛋白表达均明显增加(P<0.05,P<0.01);HG低、中、高剂量组p-FoxO1蛋白表达均明显增加(P<0.05,P<0.01)。基因检测发现,与模型组比较,HG低、中、高剂量组PI3K mRNA均明显升高(P<0.05),HG高剂量组Akt mRNA明显升高(P<0.05),HG低、中、高剂量组FoxO1 mRNA均明显降低(P<0.05)。结论:HG可缓解db/db小鼠糖脂代谢紊乱,可能与其激活肝脏PI3K/Akt/FoxO1信号通路有关。

Objective:To observe the effects of the South African herb Hoodia gordonii(HG)on glucolipid metabolism in diabetic db/db mice and explore the possible mechanisms of HG on the liver of db/db mice based on the phosphoinositide-3 kinase(PI3K)/protein kinase B(Akt)/factor forkhead protein O1(FoxO1)signaling pathway.Method:A total of 30 db/db mice were randomly divided into five groups according to fasting blood glucose:model group,metformin group(0.195 g·kg^(-1)),and low dose(0.39 g·kg^(-1)),medium dose(0.78 g·kg^(-1)),and high dose(1.56 g·kg^(-1))HG groups,with six m/m mice in each group,and another six m/m mice were set as normal group.The mice in the normal and model groups were given saline of 9 mL·kg^(-1) by gavage.Body weight,water intake,and fasting blood glucose of the mice in each group were measured weekly.After six weeks of continuous administration,serum insulin(FINS),low-density lipoprotein cholesterol(LDL),total cholesterol(TC),triglyceride(TG),alanine aminotransferase(ALT),aspartate aminotransferase(AST),urea,and creatinine(CREA)were measured,and liver sections were embedded and stained with hematoxylin-eosin(HE),periodic acid-Schiff(PAS),and oil red O.Protein expression of PI3K p85,p-Akt,and p-FoxO1 in liver was detected by immunohistochemistry.The mRNA expression of PI3K,Akt,and FoxO1 in liver tissue was detected by real-time polymerase chain reaction(Real-time PCR).Result:After six weeks of administration intervention,it was found that fasting blood glucose was significantly downregulated in mice in the three HG groups(P<0.05).The level of islet resistance index was significantly reduced in both the low and medium dose HG groups(P<0.05).The expression levels of TC,TG,and LDL were reduced in all HG groups(P<0.05,P<0.01).Pathologically,HG could alleviate hepatocyte steatosis,reduce the volume and content of lipid droplets in liver,and increase the distribution of glycogen granules in liver to some extent in mice.Immunohistochemical assays revealed that PI3K p85 protein expression was significantly increased in the low,medium,and high dose HG groups compared with the model group(P<0.01).p-Akt protein expression was significantly increased in the medium and high dose HG groups(P<0.05,P<0.01).p-FoxO1 protein expression was significantly increased in the low,medium,and high dose HG groups(P<0.05,P<0.01).Compared with the model group,PI3K mRNA was increased in low dose,medium dose,and high dose HG groups(P<0.05),and Akt mRNA was increased in high dose HG group(P<0.05).FoxO1 mRNA was decreased in low dose,medium dose,and high dose HG groups(P<0.05).Conclusion:HG can ameliorate the disorder of glucolipid metabolism in db/db mice,which may be related to its activation of the hepatic PI3K/Akt/FoxO1 signaling pathway.